Stuck coupler

hi last night around 6pm I had glued my coupler in to my av bay and this morning I was doing some sanding on the coupler so that the fin can could fit on it unfortunately I cant get them apart now even with 2 adults pulling the other way. if any one can help id appreciate it

Don't quite understand the question as a coupler and av-bay are typically the same thing... Did you glue the av-bay into your payload bay (might be a good thing depending on your design)? Are you instead talking about the coupler for the nose cone (which actually should be permanently attached to the nose cone BTW)? Or are you talking about putting the payload and the nose cone coupler together which are now stuck somehow?

ok lets say the noise is part A the av/payload bay is part B the coupler is part C and it is glued to part B and the fin can is part D and I was test fitting part D the fin can to the coupler part C but now I cant get them apart

OK, so normally a fin can would be put on the airframe which is inserted into a coupler, but in any case, lets say the fin can is stuck on the tube (whatever that is). I would put the tube/fin can combo in the freezer for an hour. I would then remove and use a hair dryer or heat gun to warm (not burn) the fin can for a minute or two, then quickly grab twist and pull. It will likely come off.

ok that sounds like a good idea but the 3 parts as is right now stuck together measures at almost 52 inch long and my freezer cant take that much

hawlk2004 said:

ok that sounds like a good idea but the 3 parts as is right now stuck together measures at almost 52 inch long and my freezer cant take that much

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Oh, OK. Where do you live? If near freezing temps, leave it outside overnight.

live in the south but only going in the upper 60s tonight to be more exact I live in austin

hawlk2004 said:

live in the south but only going in the upper 60s tonight to be more exact I live in austin

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OK, not so good... Bags of ice?

sounds good ill try it tomorrow and I don't know if it matters that the tubes are g10

Given it is tight and not glued in, I would put a bulk plate or centering ring down to rest on the coupler. Then use a board and a mallet to tap it out. Make sure to work around the edges as if it is tilted, it will bind further.

Also one end might be smaller ID than the other, so you may even have better luck on the other side (last resort).

thanks guys just tried both of yours together and its not budging im starting to think I may need to just cut it and hopefully get it out that way to save the fin can

how about you post a picture before you start cutting things apart

Does this rocket have no booster tube? I am still confused as to the design....

I think a picture would be the best.

I did this once and the problem was that some of the epoxy seeped in-between the coupler and airframe through capillary action (1/8" to 1/4" into the joint). I even kapton taped the areas that could see some epoxy and applied a coating of water soluble release.

I tried banging, pulling, and twisting. In the end I had to splice the airframe lengthwise twice (180 deg apart) and peel it off. It was filament wound G-10.

In my case the airframe was scrap and I saved the important end of the assembly.

I don't think icing it will shock the bond apart. Perhaps heat the joint with a heat gun and try spraying a can of compressed air held upside down once it's hot. That might give you the necessary thermal shock. Doubtful tho.

If it is epoxy it will come apart with heat. As suggested, a heat gun is necessary. Normal epoxy will soften up above 120F. Make sure you don't damage the tube with too much heat.

yes it is epoxy but I sanded it off I thought and it was 12 hours after aplying it and the epoxy said full cure in 3 hours

this was at 4:22 pm when I glued the coupler

this was just taken but it was stuck around 10 am the next day

Drop a bulk plate down the airframe,ontop of guilty coupler............slide 2x2 or pipe or whatever to BP ...then whack the heck out of it, while standing on airframe section.

If that doesn't do it......well.....

Do you have a wife/child/partner at home to help you? If so, you could try this.

One of you squeeze the payload tube between your legs. Each of you get a hammer and flat head screwdriver. Simultaneously chisel at the booster, one on each side. Could damage the booster, so be very careful.

blackjack2564 said:

Drop a bulk plate down the airframe,ontop of guilty coupler............slide 2x2 or pipe or whatever to BP ...then whack the heck out of it, while standing on airframe section.

If that doesn't do it......well.....

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this sounds like the best option.

RKeller said:

this sounds like the best option.

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Good idea!, might also try the same thing only set the 2x2 or pipe on the floor and slide the airframe and bulkplate over it like using a post driver, then you can hold onto the section that should be sliding off, rather than standing on the tube.

rharshberger said:

Good idea!, might also try the same thing only set the 2x2 or pipe on the floor and slide the airframe and bulkplate over it like using a post driver, then you can hold onto the section that should be sliding off, rather than standing on the tube.

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+1 I've used this method a few times when the coupler was shipped inside the BT and stuck there. If you can't get any movement when you twist and flex the stuck tubes, I believe the epoxy residue could have have glued the tubes together. I would also warm the BT tube with a heat gun on low temperature of about 150 deg. in the area that had been epoxied. This should break the epoxy bond and then you can pound it off.

Good luck!

spicer which super dx3 did you use for L1 and for all I have cooled it down and heated the fin can to pretty hot and banged on a 2x3 to a aluminum BP the rocket won and the BP only had some scraches

If Jim's bulk plate doesn't work, nothing will.